Electrode feeding mechanism



8, 1939. K. BRENKERT 2,168,697

ELECTRODE FEEDING MECHAN ISM Original Filed July 5, 1938 [NVENTOR #4 FL BFE/Wfff? T BY A TTOR/VEY Patented Aug. 8, 1939 PATENT OFFICE ELECTRODE FEEDING MECHANISM Karl Brenker't. Detroit,

Micln, assignor to Brenkert Light Projection Company, Detroit, Mich a corporation of Michigan Original application July 5, 1938, Serial No. 217,385. Divided and this application January 21, 1939, Serial No. 252,148

Claims.

The present application is a division of my copending application, Serial No. 217,385, filed July The present invention pertains to feeding I mechanism for the electrodes'of a projection arc lamp,

The high efficiency optical systems now in use in such lamps require a slow feeding mechanism for maintaining the arc accurately in the focal point of the reflector. Large movements of the electrodes, as in striking the are or replacing the electrodes, do not require a high degree of accuracy and would ordinarily be very slow if performed through the slow but accurate feeding mechanism. The principal object of the invention is to provide an arrangement affording the desired accurate feed and at the same time permitting rapid movement for the large movement of the electrodes.

A prior type of slow feed mechanism comprises a motor driven, automatically controlled, feed screw actuating a nut, formed as part of the car riage or electrode holder. The rate of feed by the screw is relatively slow for accurate feeding. When a large movement of an electrode holder is required for striking the arc or inserting new eectrodes, the feed shaft is rotated manually but the movement is necessarily slow and consumes considerable time.

The above stated object of this invention is accomplished by providing the above mentioned nut in the form of a pirnn. From the pinion extends a shaft through the wall of the housing, with a handle on its end for manual rotation. A friction clutch between this shaft and a nonrotating member resists rotation of the shaft and pinion when the feed screw is driven for normal feeding. In this operation, the pinion obviously functions as the usual nut. When a large and rapid adjustment is desired, the pinion with its shaft are turned manually by the shaft handle against the resistance of the clutch, and the pinion rolls over the feed screw in the manner of a pinion on a rack.

The invention is fully disclosed by way of example in the following description and in the accompanying drawing, in which:

Figure 1 is a side elevation of the feeding mechanism;

Figure 2 is an end view thereof;

Figure 3 is a cross section of the hand feed, and

Figures 4, 5 and 6 are details of the gearing.

Reference to these views will now be made by use of like characters which are employed to designate corresponding parts throughout.

In Figure 1 the numeral I designates a portion of the base of the projection lamp housing. The feeding mechanism includes a pair of fixed guide rods 30 and 3| running lengthwise of the base and with their ends suitably fixed in the structure. On these rods is slidably mounted a carriage 32 having an upwardly extending arm 33 which, in turn, carries a suitable clamp 34 for supporting an electrode 35. The clamp is of more or less conventional design and need not be described in detail since clamps for this purpose are well known in the art. On one of the rods is fixed another upwardly extending bracket 38 carrying an arm 31 below and along the electrode and provided with a holder or guide 38 for the tip of the electrode.

The member 32 is formed with a pair of bearings 39 and 4D alined perpendicularly to the guide rods and preferably formed near the rods. In the bearings is journaled a shaft 4|, and a pinion 42 is secured on the shaft 4| at the outer end of the bearing 39. A feed screw 43 is journaled in the base I, parallel to the rods 30 and 3| and meshes with the pinion 42 at the bottom thereof. The teeth of the pinion have a proper pitch angle for this purpose. The general combination of an electrode carriage propelled by feed screw is well known in the art and is disclosed, for example, in the patent to Preddy No. 2,065,735 of December 29, 1936.

Next to the pinion 42 is a sleeve 44 locked on the shaft 4| by any suitable means such as lugs 45 extending therefrom into suitable notches in the hub 42 of the pinion. At the outer end of the sleeve is a clutch disk 46 turning with the shaft 4| by means presently to be described. Spaced from the disk 46 is a similar disk 41 held against sliding on'the shaft, preferably by means of a collar 48 through which a pin 49 is passed into the shaft.

Between the disks 46 and 41 and spaced from both is an anchor plate 5|! mounted loosely on a collar 50' of shaft 4|. The plate 50 is held against rotation, in any suitable manner, for example, by forming a fork 5| on the member 5|) and engaging it with a sliding non-rotating member 52 formed on the carriage 32. At oppo- Site sides of the member 50 are friction or clutch plates 53 filling the space between the disks 46 and 41. The parts 45, 41, 50 and 53 are secured together by pins 44' driven therethrough and into the sleeve 44 to turn with the shaft 4|. A spring 54 surrounds the sleeve 44, with one end engaging the disk 46 and the other end engaging a collar 55 threaded on the opposite end of the sleeve, whereby the pressure of the spring and of the clutch may be adjusted.

On one end of the feed screw 43 is a pinion 55 meshing with another pinion 51 mounted on a shaft 58. The latter also carries a larger worm gear 59. An electric motor 60 is mounted at a suitable position, preferably at one side of the base I, for driving the feed screw. The shaft of the motor carries worm 6| meshing witha worm wheel 62 on a shaft 63 extending towards the worm wheel 59. The shaft 63 carries a worm 64 meshing the worm wheel 59 to complete the drive to the feed screw 43.

In the operation of this portion of the mechanism, the shaft 4| carrying the pinion 42 is held against rotation by the frictional engagement of the locked disks 46, 41 and 53 with the anchor member 50. The spring 54 is made sufficiently tight for the purpose of holding the pinion 42 from rotating while the feed screw 43 turns beneath it. In this operation the pinion 42 performs the function of a nut on the member 43 as a screw, whereby the members 32 and 33 with the clamp 44 are fed along the guide rods 30, 3|.

The carriage is moved for rapid adjustment by turning a handle 65 fixed on the shaft 4| exicriorly of the base I. In turning the shaft by this handle, the friction in the clutch is overcome and the pinion 42.rolls on the feed screw 43 as a pinion on a rack. As is Well known in the art, .auch rapid movement of the electrode holders is used in replacing electrodes, striking the arc and other approximate adjustments.

A similar mechanism 66 is provided at the other end of the feed screw and carries a support 67 for the other electrode 68. At this mechanism the feed screw is reversely threaded at 43' so that the holders are fed simultaneously in opposite directions.

Although a specific embodiment of the invention has been illustrated and described, it will be understood that various alterations in the details of construction may be made without departing from the scope of the invention, as indicated by the appended claims.

What I claim is:

An electrode feeding mechanism comprising a rotary feed screw, a guided electrode carriage, a shaft journaled in said carriage, a pinion fixed to said shaft and meshing with said screw, a non-rotatable member movable with said carriage, a clutch member secured .to turn with said shaft' and frictionally engaging said non-rotatable member with sufficient pressure to prevent rotation of said shaft and pinion during rotation of said screw, said shaft with the pinion and clutch member being manually rotatable in opposition to said frictional engagement to roll said pinion on said screw.

2. An electrode feeding mechanism comprising a rotary feed screw, a guided electrode carriage, a shaft journaled in said carriage, a pinion fixed to said shaft and meshing with said screw, a member movable with said carriage, a non-rotatable member near said shaft and anchored to the first named member, a clutch member secured to turn with said shaft and frictionally engaging said non-rotatable member with sufficient pressure to prevent rotation of said shaft and pinion during rotation of said screw, said screw, with the pinion and clutch member, being manually rotatable in opposition to said frictional engagement to roll said pinion on said shaft. I

3. An electrode feeding mechanism comprising a rotary feed screw, a guided electrode carriage, a shaft journaled in said carriage, a pinion fixed to said shaft and meshing with said screw, a nonrotatable member movable with said shaft, a clutch member secured to said shaft and frictionally engaging said non-rotatable member with sufiicient pressure to prevent rotation of said shaft and pinion during rotation of said screw, said shaft with the pinion and clutch member being manually rotatable in opposition to said frictional engagement to roll said pinion on said screw, a spring pressing said clutch member against said non-rotatable member, and means for adjusting said spring.

4. An electrode feeding mechanism comprising a rotary feed screw, a guided electrode carriage, a shaft journaled in said carriage, a pinion fixed to said shaft and meshing with said screw, a non-rotatable member adapted to move with said shaft, clutch members secured to said shaft and frictionally engaging opposite faces of said nonrotatable member with sufliclent pressure to prevent rotation of said shaft and pinion during rotation of said screw, said shaft with the pinion and clutch member being manually rotatable in opposition to said frictional engagement to roll said'pinion on said screw.

5. An electrode feeding mechanism comprising a rotary feed screw, aguided electrode carriage, a shaft journaled in said carriage, a pinion fixed to said shaft and meshing with said screw, a non-rotatable member adapted to move with said shaft, clutch members secured to said shaft and frictionally engaging opposite faces of said nonrotatable member with sufficient pressure to prevent rotatlon of said shaft and pinion during rotation of said screw, said shaft with the pinion and clutch member being manually rotatable in opposition to said frictional engagement to roll said pinion on said screw, a spring pressing one of said clutch members against said non-rotatable member, means for adjusting said spring, and stop means retaining the other clutch member against the pressure of said spring.

6. An electrode feeding mechanism comprising a rotary feed screw, a guided electrode carriage, a shaft journaled in said carriage, a pinion fixed to said shaft and meshing with said screw, a non-rotatable member adapted to move with said shaft, a clutch member secured to said shaft and frictionally engaging said non-rotatable member with sufiicient pressure to prevent rotation of said shaft and pinion during rotation of said screw, said shaft with the pinion and clutch member being manually rotatable in opposition to said frictional engagement to roll said pinion on said screw, and a spring pressing said clutch =1 member against said non-rotatable member.

'7. An electrode feeding mechanism comprising a rotary feed screw, a slidable electrode carriage, a toothed wheel rotatably supported by said carriage and meshing with said screw, frictional means normally holding said wheel against rosaid toothed member, means normally holding said members in frictional engagement with each other to prevent rotation of the toothed member during rotation of said screw, whereby said screw propels the toothed member and said carriage along the screw, said toothed member being manually rotatable in opposition to said means, to roll on said screw and displace said carriage.

9. An electrode feeding mechanism comprising a rotary feed screw, a slidable electrode carriage, a toothed wheel rotatably supported by said carriage and meshing with said screw, frictional means normally holding said wheel against rotation, whereby said screw propels said Wheei 15 and carriage along the screw, said wheel being manually rotatable in opposition to said means, to roll on said screw and displace said carriage, and means for adjusting said frictional means.

10. An. electrode feeding mechanism comprising a rotary feed screw, a slidable electrode carriage, a toothed wheel rotatably supported by said carriage and meshing with said screw, manually releasable means normally holding said wheel against rotation, whereby said screw propels said wheel and carriage along the screw, said wheel being manually rotatable in opposition to said means, to roll on said screw and displace said carriage.

KARL BRENKERT. 

